The invention is in the field of timing control of electrographic machines.
U.S. Pat. No. 4,025,186 to Hunt, Jr. et al is representative of a number of publications and commercial apparatus in which indicia on an endless web are used to control timing of a reproduction apparatus. In that apparatus an electrophotographic web has a series of perforations (sometimes called “perfs”) along one or both edges. The perforations are sensed at a position along the path of the web and the resulting indications of the presence of a perforation are sent to a logic and control means which controls the timing of various portions of the apparatus. The logic and control means may include a clock which creates an underlying set of clock pulses which are used to control the timing of the machine. The clock is regularly updated by the indications from the sensing means.